conventional keeping methods advise the use of a heating pad and honestly, they work well. I would suggest if you suspect that the heat pad isn't working or providing the correct amount of heat then measure the temperature of the hot spot with a temp gun and check that reading. If the temp is in that high 80s range then leave it. Radiant heat panels are great for keeping ambient temps up but they are just not effective enough to provide a hot spot, in my opinion, but that certainly doesn't mean it cant be done.